The present invention generally relates to magnetic recording and/or reproducing apparatus and in particular to a magnetic recording and/or reproducing apparatus for recording and/or reproducing information signals on and/or from both sides of a flexible rotary magnetic recording medium.
There is a magnetic recording and/or reproducing apparatus for recording and/or reproducing an information signal on and/or from both sides of a flexible rotary magnetic recording medium such as a floppy disk by means of a lower magnetic head mounted on a carriage and an upper magnetic head mounted on an arm which swings to and from the carriage.
In such a magnetic recording and/or reproducing apparatus, it is essential to maintain the upper magnetic head and the lower magnetic head which scan respective sides of the magnetic disk in parallel for a correct recording and/or reproducing operation. If such parallelism is lost, the magnetic heads lose the close engagement with the surface of the magnetic disk and the signal level for the recording and/or reproducing is decreased. This leads to an erroneous recording and/or reproduction of the information signal. As the upper magnetic head mounted on the arm moves with the swinging motion of the arm, it is difficult to maintain the upper magnetic head in parallel to the lower magnetic head as long as it is mounted directly on the arm. Because of this, the upper magnetic head is usually mounted on the arm via a gimbal supporting mechanism. The gimbal supporting mechanism is formed by a thin metallic plate, and maintains the upper magnetic head mounted thereon parallel to the lower magnetic head by supporting the head in a manner such that the head swings freely around two axes which cross perpendicularly to each other. Further, the arm is urged by a spring so that the upper magnetic head on the arm is pressed against the magnetic disk with a predetermined force.
However, in such a magnetic recording and/or reproducing apparatus, there is a tendency that a dropout of recorded or reproduced signal arises due to a leaping motion of the upper magnetic head when a strong vibration is applied to the apparatus. Such a vibration is transmitted from the apparatus to the lower magnetic head which is directly mounted on the apparatus, which in turn transmits the vibration to the upper magnetic head.
Another magnetic recording and/or reproducing apparatus having a similar gimbal supporting mechanism for the lower magnetic head is also proposed for improving the parallelism between the upper magnetic head and the lower magnetic head. In such an apparatus, however, there arises a problem of resonance between the gimbal supporting mechanism carrying the lower magnetic head and the gimbal supporting mechanism carrying the upper magnetic head.
Recent magnetic recording and/or reproducing apparatuses are required to perform a high density recording of information. As the recording density increases, the occurrence of the dropout of the information signal increases. Such dropout of the information signal is often caused by a vibration of the apparatus and such vibration is caused by a source such as a motor in the apparatus. Thus, the vibration proof performance required for the magnetic recording and/or reproducing apparatus becomes more severe with increased recording density.
In the magnetic recording and/or reproducing apparatus of the type aforementioned, a particularly careful design is required for the vibration proof performance, as such an apparatus involves the problem of resonance between the gimbal supporting mechanisms for the upper magnetic head and the lower magnetic head.